1. Field to which invention relates
The present invention relates to cine projection screen.
2. The prior art
A roll up cine projection screen has already been proposed which is adapted to be held taut in the extended condition for use by means of struts and is adapted to be hung by means of either of its roll up rod or its tubular casing on a carrier. Furthermore, the struts with the cine projection screen held taut on them are pivoted on the carrier about a horizontal axis parallel to the plane of the screen and are adapted to be locked in several angular positions.
With this arrangement it is possible, more particularly for the purposes of overhead projection, though also for other types of projection, to arrange for any desired oblique positioning of the plane of the screen with respect to the vertical plane and thus to produce such a setting with respect to the optic axis of the projector that distortion owing to converging lines are prevented. A condition for distortion-free projection is, however, also an alignment between the projector and the cine screen in the horizontal plane in such a manner that the optic axis of the projector passes perpendicularly through the screen plane in its diagonal point of intersection. Accordingly in the case of prior art cine screens the position of the projector in the room was fixed. It is, however, often necessary or desired to arrange the projector at another place in the room, for example in order to avoid furniture, so that the optic axis runs obliquely through the room towards the projection screen.